The Tissue Culture Core will support each of the projects by providing cells, technical support and facilities that include:\ 1. Routine isolation of primary fetal rat calvarial-derived and human derived osteoblasts as needed; 2. Maintenance of the cultures under defined experimental conditions throughout the osteoblast developmental period; 3. Maintenance of osteosarcoma and non-osseous cell lines; 4. Monitoring growth and differentiation parameters that include photography and histochemical detection procedures, cell counts, H- thymidine labelling; 5. Harvesting media and cell layers samples for assays by the Biochemistry and Molecular Biology Cores for specific experiments; 6. Preparation and sterility testing of cell culture media, screening of serum lots and reagents for the culture to ensure uniformity of cultures; 7. Collating parameters of cell growth-differentiation and tissue organization for distribution to project investigations.